According to TechCrunch, a Georgia Tech student allegedly found a way to get the phone numbers of Yo's more than 300,000 users, barrage those users' friends with Yo messages, and alter Yo messages those users tried to send to others. Yo founder Or Arbel has confirmed that the app has been dealing with security issues, though he did not mention which hacks were still active. The company has since brought in a security team to fix the problems "in the next few hours." Arbel has not yet responded to an email from Fast Company.

Yesterday, Shubham Datta, an accountant at KPMG, led a few of Silicon Valley's top VCs to believe they'd received a personal Yo from Tesla's Elon Musk. Datta, who quickly claimed the Yo username "Elonmusk," searched "justyo.co" on Twitter to figure out who else was already using the Yo app. Then Datta sent a Yo to notable Silicon Valley personalities on the app, posing as Musk. After investor Jason Calacanis announced he'd received a yo from "Elon," the Internet was convinced. Furthering the confusion, Musk, the real one this time, tweeted about the app, praising its simplicity. Musk later deleted the tweet. Datta continued the prank for a few hours before coming clean in a blog post.